In recent years, due to changes in living environment, patients or potential patients with lifestyle-related diseases (adult diseases), such as diabetes and obesity, have been increasing in number. For example, diabetes is a disease caused by abnormal saccharometabolism, and is a disease involving the risk of various distinctive complications resulting from pathologically elevated blood glucose level (glucose concentration in the blood). Dietary therapy is essential in the treatment of diabetes. However, when dietary therapy alone is not sufficiently effective, insulin or an oral hypoglycemic drug is used.
An α-glucosidase (disaccharide-degrading enzyme) inhibitor, which is one of oral hypoglycemic drugs, has an activity of delaying degradation of disaccharides to monosaccharides and absorption thereof, and therefore is capable of inhibiting postprandial rise in blood glucose level by delaying intestinal digestion and absorption of saccharides, such as starch. However, such an α-glucosidase inhibitor is not effective in the treatment of high blood glucose level not after eating, and incapable of decreasing fasting blood glucose level. Therefore, enhancement of the hypoglycemic activity of such a hypoglycemic drug has been desired. In addition, α-glucosidase inhibitors have strong side effects including meteorism, feeling of fullness, abdominal discomfort, and diarrhea.
Patent Literature 1 discloses a saccharide digestion inhibitory agent comprising a combination of an α-glucosidase inhibitor and nonpathogenic lactic acid-producing viable cells, and a saccharide digestion inhibitory composition comprising the same. Patent Literature 1 describes that the combination of an α-glucosidase inhibitor and lactic acid-producing viable cells was effective in preventing diarrhea etc. Non Patent Literature 1 discloses that concomitant administration of acarbose and a lactic acid bacterium Lactobacillus casei YIT9029 improved side effects of acarbose, such as abdominal fullness. Patent Literature 2 and 3 disclose a health food composition comprising an ingredient with α-glucosidase inhibitory activity and an ingredient with intestinal environment-improving activity, lactic acid bacteria for example, as a health food composition having no risk of side effects and usable for preventing or improving obesity and lifestyle-related diseases, such as diabetes. In Patent Literature 2 and 3, it is stated that since the composition comprising an ingredient with intestinal environment-improving activity, lactic acid bacteria for example, inhibits intestinal decomposition, promotes regular bowel movement, and prevents constipation, the composition is promising for decreasing obesity and preventing colorectal cancer. Patent Literature 4 discloses a hypoglycemic drug comprising lactic acid bacterial cells as an active ingredient.
However, Patent Literature 1 to 4 and Non Patent Literature 1 have no description regarding enhancement of the activity of the hypoglycemic drugs. Therefore, there is room for improvement to achieve a better hypoglycemic activity useful for prevention or treatment of lifestyle-related diseases, such as diabetes and obesity.